Disc changer

ABSTRACT

The invention provides a disc changer including a plurality of trays which can be moved respectively in a horizontal direction, a tray driving gear unit capable of shuttling the trays between a standby position and a disc exchange position, a gear driving mechanism for driving the tray driving gear unit, a tray triggering unit capable of locking/unlocking the trays in the standby position, pushing all trays to engage with the tray driving gear unit after unlocking the trays, and driving the trays toward the disc exchange position, wherein the tray driving gear unit can be used for checking the discs by driving all trays to protrude outward from the mechanical chassis to the disc exchange position, and can drive the trays individually from the disc exchange position to the standby position from top to bottom, thereby each disc can be checked until its tray is closed.

TECHNICAL FIELD

The present invention relates to a disc changer, particularly but notexclusively to a disc changer that stores a plurality of discs therein,transports a disc selected from a plurality of discs, and performsrecording and/or reproducing information signal on the disc. In thespecification, the wording of “recording/reproducing an informationsignal on a disc” refers to “at least one of recording an informationsignal on a disc and reproducing an information signal from a disc” asan abbreviated form of expression.

BACKGROUND ART

A conventional disc changer normally has a plurality of trays housedwithin a casing, with each tray arranged to carry an optical disc. Inone known type, the disc changer includes a single selected tray or amain tray with a selected sub tray and by depressing an eject button themain tray carries the sub tray to move from a standby position withinthe casing to protrude outward to a disc exchange position for inputtingor exchange of a disc. A disc can then be placed on the sub tray which,upon receiving a suitable signal, carries the disc together with themain tray into the standby position. At the standby position, the subtray departs from the main tray to carry the disc to a storage rackwithin the casing which can hold a plurality of disc to be played. Withthis configuration, only one disc can be input or exchanged at a time,and to load a disc or replace a disc, each of the rest of the trays haveto be ejected individually transported by the main tray. This cangreatly inconvenience an end user since, more often than not, afterkeeping the discs inside the disc changer for a period of time, the userwould not be able to remember the correct arrangement of the discsinside the disc changer and to find out, it will be necessary to inspectthe contents of each tray.

Another known type of disc changer has a number of sub-trays arranged ona main tray and the main tray is used to transport all the sub-trays toa disc exchange position. However, it is necessary to have a main traywhich increases manufacturing costs of the disc changer and loading andreplacement of disc are still inconvenient. Further, returning of eachtray to its standby position within the casing is inefficient.

Some disc changers include a “Disc Check” function which allows a numberof trays to be ejected at different distances away from the casing sothat the trays partially overlap each other. This allows the content ofthe trays to be checked. However, this method is suitable only if thedisc changer has a few trays and further, such a function does not allowdiscs to be loaded/replaced.

Further, in the conventional disc changers mentioned above, when thetrays are at the standby position waiting to carry a selected disc to aposition for reproducing/recording operation, the tray is engaged with atray drive gear train, and kept in this position only by friction forceof the gear train engagement and a tension of a motor belt.Consequently, the trays are not held securely and misalignment of thetrays can occur if the disc changer is transported when the trays are insuch a position.

If a locking device is provided to lock all the trays, an additionaldriving source is needed to unlock the locking state prior to drive thetrays. In general, a complicated design is needed to lock the trays. Asa locking device in a conventional disc changer usually needs some timeto activate the locking function, a shifting of the tray from itsstandby position easily happens during the tray “non-lock” period. Thisproblem is exacerbated when the “non-lock” period is long, and occursmany times during the disc changer operating period.

SUMMARY OF INVENTION

The present invention has been developed in view of the aforementionedtechnical problems and aims to provide a new and useful disc changerdevice. A preferred embodiment of the invention is a disc changercapable of ejecting all trays from the standby position to a discexchange position where the discs can be exchanged, and capable also ofclosing the trays one by one from top tray to bottom one. Furthermore,the preferred embodiment makes it possible to check directly andvisually the discs stored inside the disc changer automatically with asingle button operation.

According to a first aspect of the present invention, there is provideda disc changer for storing a plurality of discs, transporting a discselected from the plurality of discs, and performingrecording/reproducing information signal on the disc, the disc changercomprising: a plurality of trays which respectively can be loaded withdiscs, can be moved substantially in a horizontal direction parallel tomain surfaces of the discs, and are stacked substantially in a verticaldirection perpendicular to the main surfaces of the discs; a traydriving gear unit capable of shuttling the trays between a standbyposition in which the trays are stored in a mechanical chassis as ahousing of the disc changer and a disc exchange position in which thetrays are protruded outward from the mechanical chassis thereby thediscs can be put on the trays and removed form the trays; a gear drivingmechanism driven by an electrical motor to generate driving force fordriving the tray driving gear unit; a tray triggering unit capable oflocking/unlocking the trays in the standby position, the unit capable ofpushing all trays to engage with the tray driving gear unit afterunlocking the trays and capable of driving the trays outward from themechanical chassis toward the disc exchange position; arecording/reproducing unit for recording and/or reproducing informationsignal on a disc placed on a turntable; and an elevation unit capable ofmoving the recording/reproducing unit with the turntable in a verticaldirection to align the recording/reproducing unit to a tray and place adisc on the tray onto the turntable; wherein the tray driving gear unitis commonly used for checking the discs by driving all trays to protrudeoutward from the mechanical chassis to the disc exchange position, thetray driving gear unit is capable of individually driving the trays fromthe disc exchange position to the standby position from top to bottom ina operation of closing discs, and each disc can be checked until it isclosed.

According to the configuration of the first aspect of the invention, thetray driving gear unit is capable of driving the trays from the standbyposition to the disc exchange position with an all-at-once operation. Atthis time all tray driving gears of the tray driving gear unit rotate ina tray opening direction as one solid gear for driving the plurality oftrays. Further, when the tray driving unit rotates in an oppositedirection the trays are driven one by one from the top tray to thebottom tray. Thus, it is possible to eject all trays at once, andexchange all discs from the top tray to bottom tray. This simplifies theoperation of exchanging all discs in the disc changer. While all thetrays are protruding, all the discs can be checked at all time. The sametray driving gear unit is commonly used for both shuttling the traysbetween the standby position and the disc exchange position and discchecking function, thereby it is possible to simplify the design of thetray driving gear unit, simplify the disc changer operation, shorten thechanging time and reduce the possibility of tray jams.

Further, in a second aspect of the present invention, there is provideda disc changer for storing a plurality of discs, transporting a discselected from the plurality of discs, and performingrecording/reproducing information signal on the disc, the disc changercomprising: a plurality of trays which respectively can be loaded withdiscs, can be moved substantially in a horizontal direction parallel tomain surfaces of the discs, and are stacked substantially in a verticaldirection perpendicular to the main surfaces of the discs; a traydriving gear unit capable of shuttling the trays between a standbyposition in which the trays are stored in a mechanical chassis as ahousing of the disc changer and a disc exchange position in which thetrays are protruded outward from the mechanical chassis thereby thediscs can be put on the trays and removed form the trays; a gear drivingmechanism driven by an electrical motor to generate driving force fordriving the tray driving gear unit; a tray triggering unit capable oflocking/unlocking the trays in the standby position, the unit capable ofpushing all trays to engage with the tray driving gear unit afterunlocking the trays and capable of driving the trays outward from themechanical chassis toward the disc exchange position; arecording/reproducing unit for recording and/or reproducing informationsignal on a disc placed on a turntable; and an elevation unit capable ofmoving the recording/reproducing unit with the turntable in a verticaldirection to align the recording/reproducing unit to a tray and place adisc on the tray onto the turntable; wherein the tray driving gear unitcan be commonly used for checking the discs by driving all trays otherthan a tray above the recording/reproducing unit to protrude outwardfrom the mechanical chassis to the disc exchange position, the traydriving gear unit is capable of individually driving the trays from thedisc exchange position to the standby position from top to bottom in aoperation of closing discs, and each disc can be checked until it isclosed.

According to the configuration of the second aspect of the invention,the tray driving gear unit is capable of driving all trays other thanthe tray above the recording/reproducing unit from the standby positionto the disc exchange position with an all-at-once operation. At thistime all tray driving gears of the tray driving gear unit other than forthe tray above the recording/reproducing unit rotate in a tray openingdirection as one solid gear for driving all trays other than the trayabove the recording/reproducing unit. Further, when the tray drivingunit rotates in an opposite direction the trays are driven one by onefrom the top tray to bottom tray. Thus, it is possible to eject alltrays other than the tray above the recording/reproducing unit at once,and exchange all discs other than the tray above therecording/reproducing unit from top tray to bottom tray. This simplifiesthe operation for exchanging all discs other than the tray above therecording/reproducing unit in the disc changer. While all the trays areprotruding, the discs can be checked be done at all time. The same traydriving gear unit can be commonly used for both shuttling the traysbetween the standby position and the disc exchange position and discchecking function, thereby it is possible to simplify the design of thetray driving gear unit, simplify the disc changer operation, shorten thechanging time and reduce the possibility of tray jams.

Furthermore, in a third aspect of the present invention, there isprovided an optical disc changer for performing at least one of theoperations of reproducing information from an optical disc or forrecording information thereto, the apparatus comprising: a turntable; arecording/reproducing unit operative to perform at least one of theoperations of recording and/or reproducing an information signal on anoptical disc placed on the turntable; a plurality of trays for carryingrespective optical discs; a housing for receiving the plurality oftrays; a mechanism for placing a disc on a selected one of the traysonto the turntable; a tray driving gear unit operative to drive thetrays to a disc exchange position in which the trays are ejected fromthe housing for loading or removal of respective optical discs, and alsooperative to withdraw the plurality of trays from the disc exchangeposition to the standby position, the tray driving gear unit comprisinga plurality of tray drive gears and a coupling mechanism for couplingthe tray drive gears together, the tray driving gear unit beingconfigurable into a RESET configuration in which the tray drive gearsare coupled together for rotation together in a tray-opening rotationaldirection; a tray triggering unit for locking the trays in a standbyposition in which the trays are received within the housing, forreleasing the trays, and for driving the trays from the standby positionto a position in which the trays are coupled to respective tray drivegears of the tray driving gear unit while the tray driving gear unit isin the RESET configuration; whereby rotation together of the tray drivegears in said one tray-opening direction drives the trays together tothe disc exchange position.

From the RESET configuration, the tray drive gears can be rotatedindividually in the opposite rotational direction, which allows thetrays to be withdrawn individually into the housing.

An alternative, but more specific, expression of the third aspect of theinvention is a disc changer for storing a plurality of discs,transporting a disc selected from the plurality of discs, and performingrecording/reproducing information signal on the disc, the disc changercomprising: a plurality of trays which respectively can be loaded withdiscs, can be moved substantially in a horizontal direction parallel tomain surfaces of the discs, and are stacked substantially in a verticaldirection perpendicular to the main surfaces of the discs; a traydriving gear unit capable of shuttling the trays between a standbyposition in which the trays are stored in a mechanical chassis as ahousing of the disc changer and a disc exchange position in which thetrays are protruded outward from the mechanical chassis thereby thediscs can be put on the trays and removed form the trays; a gear drivingmechanism driven by an electrical motor to generate driving force fordriving the tray driving gear unit; the tray triggering unit capable oflocking/unlocking the trays in the standby position, the unit capable ofpushing all trays to engage with the tray driving gear unit afterunlocking the trays and capable of driving the trays outward from themechanical chassis toward the disc exchange position; arecording/reproducing unit for recording and/or reproducing informationsignal on a disc placed on a turntable; and an elevation unit capable ofmoving the recording/reproducing unit with the turntable in a verticaldirection to align the recording/reproducing unit to a tray and place adisc on the tray onto the turntable; wherein the tray driving gear unithas a series of tray drive gears and can rotate to RESET condition inwhich all drive gears can rotate as all-at-once, and wherein the traysat the standby position are not engage with the tray driving gear unit,after the tray driving gear unit rotates to RESET condition, the traytriggering unit moves and pushes the trays to engage with the traydriving gear unit.

According to the configuration of the third aspect of the invention, thetray driving gear unit has a series of tray drive gears and can rotateto RESET condition, and the trays at the standby position are engagedwith the tray driving gear unit by the tray triggering unit after thetray driving gear unit rotates to RESET condition. Thus, for eachexchange of a disc, the trays protrude to the disc exchange position andreturn to the standby position one by one from top to bottom. Thissimplifies the operation of exchanging all discs, since it is possibleto put a disc onto any of the empty tray without opening the trays oneby one.

In an embodiment of the third aspect of the invention, the tray drivinggear unit is provided with a shaft gear body, comprising a shaft gearconnected to a driving source and a shaft on which the tray drive gearsare mounted and stacked in a laminated manner, and each tray is drivenby a single tray drive gear.

According to the embodiment, the tray drive gears are separate from theshaft gear body, therefore the tray driving gear unit can bemanufactured much more easily in comparison with one body construction.

Also, in another embodiment of the third aspect of the invention, thetray driving gear is provided with a shaft gear body, comprising a shaftgear connected to a driving source and a shaft on which the tray drivegears are mounted and stacked in a laminated manner, a top level traydrive gear is fixed to the shaft gear body and rotates as one bodytherewith at all times; and each drive gear has a rib profile as astopper rib extending along with an axis of the shaft by a predeterminedamount, when an upper level tray drive gear's stopper rib pushes to alower level tray drive gear's stopper rib in a rotational direction ofthe upper level tray drive gear, the lower level tray drive gear isforced to rotate in the rotational direction of the upper level traydrive gear.

According to the embodiment, the tray drive gears are separate from theshaft gear body, therefore the tray driving gear unit can bemanufactured much easier in comparison with one body construction.Further, a top level tray drive gear fixed to the shaft gear bodyrotates as one body therewith at all time, and the rotational movementof the top level tray drive gear is transferred to the lower level drivegear through the stopper ribs thereof. Thus, all tray drive gears aredriven to rotate one by one through the stopper ribs.

Furthermore, in still another embodiment of the third aspect of thepresent invention, at least one spacer ring is provided between two traydrive gears adjacent to each other, the spacer ring allows the upperlevel tray drive gear to have an additional rotation before it drivesthe lower level tray drive gear, thereby the additional rotation isprovided to each tray drive gear.

According to the embodiment, the additional rotation is provided to eachtray drive gear by at least one spacer ring placed between two traydrive gears adjacent to each other. The spacer ring can acts as a dummygear in the rotational movement of the tray driving gear unit, and canreduce the size of the tray drive gear, because, in a case that the traydriving gear unit does not have a spacer ring, the drive gear pitchdiameter needs to provide a total circumference equivalent to a totalstroke for one complete rotation, and this increases the diameter of thetray drive gear.

Furthermore, in still another embodiment of the third aspect of thepresent invention, each spacer ring has stopper ribs which are same asthe stopper ribs of the tray drive gear, the size in a rotationaldirection of the stopper ribs is designed to be equivalent to a multipleof gear teeth pitching angle, and the tray drive gear teeth align afterall stopper ribs contact each other, thereby the all tray drive gear canbe driven to move all trays to the disc exchange position evenly.

According to the embodiment, an upper level tray drive gear's stopperrib pushes to a lower level tray drive gear's stopper rib, through thespacer ring's stopper ribs, in a rotational direction of the upper leveltray drive gear, and the lower level tray drive gear is forced to rotatein the rotational direction of the upper level tray drive gear. Thus,the rotational movement of the top level tray drive gear is transferredto the lower level drive gear through the stopper ribs, and all traydrive gears are driven to rotate one by one through the stopper ribs.Specifically, the size in a rotational direction of the stopper ribs isdesigned to equivalent to a multiple of gear teeth pitching angle,therefore the stopper ribs can contact to each other more in a morestable way.

Furthermore, in still another embodiment of the third aspect of thepresent invention, a total rotational stroke of the tray drive gearbefore the lower level tray drive gear starts to rotate is equivalent tothe total stroke for moving a tray from the disc exchange position tothe standby position.

According to the embodiment, it is possible to provide the tray drivinggear unit with a dummy turn which is equivalent to the total stroke formoving a tray from the disc exchange position to the standby position,thereby the size of the tray drive gear can be reduced.

Furthermore, in still another embodiment of the third aspect of thepresent invention, the first gear tooth of the tray's gear rack has ashape profile for easy engagement of trays to tray driving gear unitafter triggered by the tray triggering unit.

According to the embodiment, owing to the shape profile of the firstgear tooth of the tray's gear rack, the tray's gear rack can be easilyengaged with the tray driving gear unit after triggered by the traytriggering unit. Thereby, the tray can start to move smoothly by thetray driving gear unit.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a perspective view showing a disc changer according to thepresent embodiment in a state that all trays are opened;

FIGS. 2( a) to 2(e) are schematic side views of the disc changer showingvarious operations of the trays and a recording and/or reproducing unitof the disc changer;

FIG. 3( a) is a plan view of the disc changer according to theembodiment;

FIG. 3( b) is an enlarged perspective view of a part of a disc tray;

FIG. 4 is a side view of the disc changer shown in FIG. 3( a);

FIG. 5 is a sectional view of the disc changer taken along line L5-L5 inFIG. 3( a);

FIG. 6 is a plan view showing a detail of tray opening mechanism of thedisc changer;

FIG. 7 is a bottom view of FIG. 6 focusing the tray triggering unit;

FIGS. 8( a) and 8(b) are plan views of a focused part of the discchanger showing a moving process of the trigger slide plate fortriggering trays;

FIGS. 9( a) to 9(c) are plan views of the trigger slide plate showing amoving sequence thereof for triggering trays and locking/unlocking traysin a standby position;

FIG. 10( a) is an explanatory drawing showing various locations of aboss portion of the trigger slide plate;

FIG. 10( b) is a side view of the trigger slide plate;

FIGS. 11( a) to 11(c) are plan view of a tray driving gear unit showingengagement and disengagement thereof to the tray;

FIGS. 12( a) to 12(d) are explanatory drawings showing a sequence of amotion of a tray lock lever;

FIG. 13( a) is an exploded view of a tray driving gear unit;

FIG. 13( b) is a perspective view of a complete assembly of the traydriving gear unit;

FIG. 14 is a perspective view of the tray driving gear unit and a gearmechanism for driving it;

FIGS. 15( a) to 15(h) are explanatory drawings showing a sequence of“RESET” the tray driving gear unit;

FIG. 16 is a side view of the tray driving gear unit with trays at thestandby position;

FIG. 17 is an enlarged perspective view of the tray driving gear unitwith trays at the standby position;

FIGS. 18( a) to 18(d) are explanatory drawings showing a sequence of thetray driving gear unit for driving trays one by one from top to bottom;

FIG. 19( a) is a top view of the disc changer;

FIG. 19( b) is a side view showing the tray driving gear unit whichengages with trays;

FIGS. 20( a) to 20(c) are side views showing a sequence of closing thetop tray from the disc exchange position to the disc standby position;

FIG. 21 is a plan view showing a total layout of a driving (gear)mechanism in the disc changer according to the embodiment;

FIG. 22 is a plan view showing the details of a main part of FIG. 21;

FIG. 23 is a perspective view showing a gear engagement around aswitching gear.

FIG. 24 is a perspective view showing a gear engagement around afunction gear.

FIGS. 25( a) and 25(b) are schematic side views showing a first geartrain changing system by a switching gear;

FIGS. 26( a) and 26(b) are schematic side views showing the second geartrain changing system by a function gear;

FIG. 27 is a perspective view of a function lever and a function gear inan assembly condition;

FIG. 28( a) is a plan view showing a cam gear;

FIG. 28( b) is a perspective view showing the outer profiles at thelower side of the cam gear;

FIG. 29 is a block diagram for explaining a switching mode of thedriving mechanism in the disc changer;

FIG. 30 is a plan view showing a gear train of a tray open/close systemin the disc changer;

FIGS. 31( a) to 31(d) are plan views showing the sequence of trayopening operation which mainly controlled by cam gear;

FIGS. 32( a) and 32(b) are perspective views showing a trigger gear anda trigger slide plate;

FIG. 33 is a plan view showing a gear train of elevation system in thedisc changer;

FIG. 34 is a perspective view showing the components of the elevationunit;

FIG. 35 is a side view showing a step-like cam profile on a right sideUD rack;

FIGS. 36( a) and 36(b) are perspective views respectively showing therecording/reproducing section at an upper most position and a lower mostposition;

FIG. 37 is a plan view showing a gear train of tray play/stock system ina disc changer;

FIGS. 38( a) and 38(b) are plan views showing the movement of drivingtrays between the disc standby position and the recording/reproducingposition;

FIG. 39 is a perspective view showing the components of the tray drivingrack unit;

FIGS. 40( a) to 40(d) are enlarged plan views showing a moving sequenceof a tray catch lever to drive trays from disc standby position to therecording/reproducing position;

FIGS. 41( a) to 41(d) are enlarged plan views showing a sequence of anoperation of tray driving rack unit;

FIG. 42 is a side view showing a clamper unit in an unclampingcondition;

FIG. 43 is a side view showing the clamper unit in a clamping condition;

FIG. 44 is an enlarged plan view showing a locking system for trays atdisc standby position;

FIG. 45( a) is a plan view of a tray lock lever;

FIG. 45( b) is a perspective view of the tray lock lever.

FIG. 46 is a diagram showing a relationship between cam gear positionsand locking types of the tray;

FIGS. 47( a) to 47(c) are enlarged plan views showing tray lock leversin locking trays at standby position;

FIG. 48 is a perspective view of the disc changer from front side in astate in which the trays are locked at the standby position;

FIG. 49 is a perspective view of the disc changer from rear side in astate in which the trays are locked at standby position;

FIG. 50 is a plan view showing a locking mechanism at therecording/reproducing section.

FIGS. 51( a) and 51(b) are perspective views showing a first lock leverand a second play gear in a lock condition;

FIGS. 52( a) and 52(b) are a plan view and a perspective view showing afirst lock lever 93 as a locking device;

FIGS. 53( a) and 53(b) are a plan view and a perspective view showingthe first lock lever;

FIG. 54( a) is a plan view showing a locking condition of the first locklever.

FIG. 54( b) is a plan view showing an unlocking condition of the firstlock lever;

FIG. 55 is a perspective view showing a condition where the cam gearrotates to a position for unlocking the first lock lever;

FIG. 56 is a plan view showing a second lock lever as a locking devicein the changer mechanism;

FIG. 57 is a perspective view showing a second lock lever and a secondUD gear in an unlock condition;

FIG. 58( a) is a plan view showing a locking condition of the secondlock lever;

FIG. 58( b) is a plan view showing an unlocking condition of the secondlock lever;

FIG. 59 is a plan view of a cam gear explaining an operation thereofwhen it rotates in a clockwise and a counter-clockwise direction;

FIG. 60 is a perspective view show a condition where the cam gear isrotated to a position for unlocking the second lock lever;

FIG. 61 is a perspective view showing another locking system thatprevents a movement of the recording/reproducing section when one of thetray is at the recording/reproducing position; and

FIG. 62 is a locking system summary table at recording/reproducingsection.

DETAILED DESCRIPTION OF THE INVENTION

Hereinafter, preferred embodiments of the present invention will bedescribed with reference to the accompanied drawings.

FIG. 1 is a perspective view showing a disc changer 1 according to thepresent embodiment in a state that all trays T are opened. As shown inFIG. 1, the disc changer 1 is provided with a plurality of trays T. Inthe embodiment, the disc changer 1 is provided with five trays T(labeled T1-T5), but in other embodiments there may be a differentnumber of trays T. Each tray T is capable of carrying a disc D thereon.The disc D may be a large disc Da having a larger diameter of 12 cm or asmall disc Db having a smaller diameter of 8 cm depending on user'srequirement, for example. The disc changer 1 is also provided with agenerally box-like shaped mechanical chassis 3 which serves as a housingor an outer frame body thereof.

Each tray T can be stored within the mechanical chassis 3 in a statethat they are stacked in a substantially vertical directionperpendicular to a main surface of the disc D, and can be moved in asubstantially horizontal direction parallel to the main surface of thedisc D.

FIGS. 2( a) to 2(e) are schematic side views of the disc changer 1showing various operations of the trays T and a recording/reproducingsection 70 of the disc changer 1. As shown in the drawings, the discchanger 1 is provided with, as tray positions, three different positionswhich are different in horizontal direction to each other. That is, adisc exchange position X in which the tray T protrudes outward from themechanical chassis 3, a standby position Y in which the tray T is storedin the mechanical chassis 3 and a recording/reproducing position Z inwhich the tray T is correctly positioned to interact with therecording/reproducing section 70. The recording/reproducing position Zis set at near a back in the mechanical chassis 3, and the standbyposition Y is set at near an entrance of the mechanical chassis 3.

Among the FIGS. 2( a) to 2(e), FIG. 2( a) shows a RESET state. In thisRESET state, all the five trays T except for the highest level tray T1are stored and aligned with one another at the standby position Y. Therecording/reproducing section 70 is movable in a vertical direction, andis shown in FIG. 2( a) at its highest position. The highest level trayT1 is stored at recording/reproducing position Z.

FIG. 2( b) shows a series of disc exchanging states. In the state shownin FIG. 2( b-1), all trays T are moved to the disc exchange position Xat once. It will be noted that the discs D (Da or Db) can be put on thetrays T or removed from the trays T by moving the trays T one by onefrom top to bottom, as shown in the sequence of images 2(b-1) to 2(b-5).

FIG. 2( c) shows a series of recording/reproducing states. In each ofthese states, a specified tray T is moved to the recording/reproducingposition Z form the standby position Y and is stopped there, thereaftera recording or reproducing signal on the disc D on the specified tray Tis started. The disc D which is to be performed the recording orreproducing signal thereon can be exchanged by exchanging the specifiedtray T. With respect to FIG. 2( c-1), the arrangement of the trays T isthe same as the RESET shown in state FIG. 2( a), because the highesttray T1 is located to the recording/reproducing unit 70. The sequence ofimages FIG. 2( c-1) to FIG. 2( c-5) show how the trays T aresuccessively moved to the recording/reproducing position Z.

Moreover, FIG. 2( d) shows a series of disc exchanging states during therecording and/or reproducing operation, for example a disc exchangingwhile tray T1 is at the recording/reproducing position Z. FIG. 2( d-1)shows the disc changer 1 in the same configuration as FIG. 2( c-1) inwhich all the discs D are in the disc exchange position X. In the stateshown in FIG. 2( d-2), except for the tray T1 which supports a disc Dduring the recording or reproducing operation, all trays T (T2-T5) arepositioned at the disc exchange position X, and in the sequence ofimages 2(d-2) to 2(d-5) the trays T are closed one by one from top tobottom, so that a disc D can be put on and/or removed from each tray T(T2-T5) when that tray T is the uppermost one at the disc exchangeposition X.

FIG. 2( e) shows in FIG. 2(1-e) to 2(e-5) a series of images which arerespective fully-open states of the trays T during the recording and/orreproducing operation. In each of these states a single specified tray Tis at the recording or reproducing position Z, and all the other trays Tare positioned at the disc exchange position X. A disc D can be put onthe corresponding tray or removed from it when the tray T is in the discexchange position X, while the disc D on the specified tray T in therecording or reproducing position Z is experiencing the recording orreproducing operation.

The whole configuration of a disc changer 1 according to an embodimentof present invention which performs the above-described operations willbe explained in accordance with FIGS. 3 to 5.

FIG. 3( a) is a plan view of the disc changer 1 according to theembodiment, FIG. 3( b) is an enlarged perspective view of a part of atray T, FIG. 4 is a side view of the disc changer 1 shown in FIG. 3, andFIG. 5 is a sectional view of the disc changer 1 taken along line L5-L5of FIG. 3( a).

As shown in FIGS. 3 to 5, each tray T has a large diameter step Ta and asmall diameter step Tb on the upper surface. Thereby, a selected one oflarge disc Da and a small disc Db having different diameters (12 cm and8 cm) to each other can be loaded on the tray T.

In the tray T, grooves Tc are formed on both right and left sides at theback, a gear rack Td is formed on one side (the left side, for example),a step up surface Te is formed on the left side at the back in rearportion of the tray T. Also, as shown in FIG. 3( b), a rib Tf is formedon the left side at the back in rear portion of the tray T, underneaththe rack Td. Further, an opening of a hook profile Tg is formed on theleft side of the rear portion of a tray support.

A plurality of (e.g. five) trays T are separately arranged in parallelwhile being stacked substantially in a vertical direction, that is,perpendicular to the main surfaces of the discs D. Moreover, as shown inFIG. 3, the trays T are supported by guide ribs 3 a provided inside onthe right and left sides of the mechanical chassis 3, so that the traysT can move substantially in a horizontal direction (lateral direction),that is in parallel with main surfaces of the disc D.

The trays T are moved by a tray driving gear unit 20 provided on theleft side of the mechanical chassis 3, between the disc exchangeposition X and the standby position Y. A tray driving rack unit 60 isprovided on the left side rearward of the trays T. The tray driving rackunit 60 is mounted on an UD base 5, moves and aligns itself to aspecified tray address, and transfers trays T to therecording/reproducing section 70. It is to be noted that FIGS. 3 to 5show a state in which the highest level tray T1 (the first tray) islocated at the disc exchange position X.

The disc recording/reproducing section 70 is provided behind the trays Tlocated at the standby position Y. The disc recording/reproducingsection 70 is supported by a left guide rib 3 b and a right guide rib 3c which are formed on the sides of mechanical chassis 3, and is moved ina up and down direction (vertical direction) by an elevating unit 30which will be discussed later.

A triggering unit 50 (shown in FIG. 4, and described in more detailbelow with reference to FIG. 31) is provided on the left side of thedisc changer 1, and moves in a direction parallel to the left sidesurface of the mechanical chassis 3 to push the trays T so as to engagethem with the tray driving gears unit 20. Further, there is provided adriving mechanism 100 (described below with reference to FIG. 21)composed of a motor for driving each part, gear trains, a plunger unitfor switching between gear trains, and a detection switch, under thetrays T located at the standby position Y.

As mentioned above, the tray driving gear unit 20 is located on the leftside of the mechanical chassis 3, and an open switch lever 27 fordetecting trays T to be driven toward the disc exchange position X isprovided at the vicinity of the tray driving gear unit 20. A gear cover28 is mounted to cover a predetermined part of the top of the mechanicalchassis 3, including the top of the tray driving gear unit 20 and theopen switch lever 27. Thereby, longitudinal (vertical) axes of the traydriving gear unit 20 and the open switch lever 27 are correctly andstably positioned in relation to each other. Moreover, a top cover 4 ismounted on the top of the mechanical chassis 3 to increase the stiffnessof the mechanical chassis 3 and to protect it from dust.

FIG. 6 is a top view showing a detail of the tray opening mechanism ofthe disc changer 1. The tray opening system includes the trays T, thetray driving gear unit 20 capable of driving trays T from the standbyposition Y to the disc exchange position X, and a trays triggering unit50 having a trigger slide plate 52. The trigger slide plate 52 is movedby a trigger gear 51 and a cam gear 114 to lock/unlock trays T atstandby position and pushes all trays T to engage them with the traydriving gear unit 20. The trigger slide plate 52 moves by sliding at theside of mechanical chassis 3, while a boss portion 52 c on the triggerslide plate 52 moves to follow cam profiles 3 d on both the top andbottom of mechanical chassis 3.

FIG. 7 is a bottom view of a portion of the section of the disc changer1 shown in FIG. 6, focusing on the tray triggering unit 50. As shown inFIG. 7, the trigger gear 51 with a gear rack 51 b is connected to thecam gear 114 by a boss 51 a is fitted into a groove 114 b (see FIG. 6)of the cam gear 114. When the cam gear 114 is rotated, the boss 51 a isdriven in accordance with a profile of the cam groove 114 b, thereby thetrigger gear 51 is rotated around a supporting boss 51 c. Thus, a gearrack 51 b on the trigger gear 51 which engages with a rack profile 52 bof the trigger slide plate 52 will push the trigger slide plate 52 tomove in forward direction, and then push trays T at a trigger rib Th(see FIG. 8( b)).

A tray lock lever 53 is arranged between the trays T and the triggerside plate 52. The tray lock lever 53 is provided with a locking profile53 a (a convex part, for example) for locking trays T at standbyposition Y. The locking profile 53 a controls the trays T at the standbyposition by contacting surfaces Tk and Tm of a recess formed on the sideof the trays T.

FIGS. 8( a) and 8(b) show a moving process of the trigger slide plate 52for triggering trays T. Boss shaped portions 52 c are provided on thetop and the bottom of the trigger slide plate 52. The boss portion 52 cis fitted into a cam groove 3 d formed on the top and the middle of themechanical chassis 3. The cam groove 3 d includes three moving pathsP1-P3 for the boss portion 52 c of the trigger slide plate 52.

A moving path P1 is a “HOME” path for the boss portion 52 c of thetrigger slide plate 52, a moving path P2 is a “TRIGGER” path P3 and amoving path P2 is a “TRANSITION” path located between the “HOME” path P1and the “TRIGGER” path P3.

FIG. 8( b) shows the boss portion 52 c of the trigger slide plate 52 inthe “TRIGGER” path P3, the driving rib 52 a of the trigger slide plate52 is touching the trigger rib Th of the tray T, and ready to push traysT to move towards the tray driving gear unit 20.

FIGS. 9( a) to 9(c) show a moving sequence of the trigger slide plate 52for triggering the trays T and locking/unlocking the trays T in thestandby position Y. FIG. 9( a) shows the trigger slide plate 52 at“HOME” position. A first protrusion profile 52 e is touching a rib 53 bprotruding from the tray lock lever 53, thereby a movement of the traylock lever 53 in arrow F or arrow E direction is prevented. The lockingprofile 53 a is touching the surfaces Tk and Tm, thereby trays T are“locked” at the standby position Y. When the boss portion 52 c of thetrigger slide plate 52 moves to the “TRANSITION” path, the firstprotrusion 52 e moves away from the rib 53 b, as shown in FIG. 9( b).However, the tray lock lever 53 will remain in the same condition asFIG. 9( a).

This is due to a function of a plastic spring 53 d of the tray locklever 53. The plastic spring 53 d does not allow the tray lock lever 53to rotate in the direction of the arrow E and urge the tray lock lever53 towards the direction of the arrow F, if a bending force is appliedon the plastic spring 53 d. Before the driving rib 52 a of the triggerslide plate 52 reaches so as to touch the surface Th of a recess formedon tray T as shown in FIG. 9( c), the second protrusion 52 d alreadypushes a convex part 53 c of the tray lock lever 53 to another level.Thus, the tray lock lever 53 rotates in direction of arrow E and“unlocks” trays T.

FIG. 10( a) explains the various locations of the boss portion 52 c ofthe trigger slide plate 52 from a “HOME” position Q1 to a “TRIGGER”position Q3 and from a “TRIGGER” position Q4 to a “HOME” position Q7. Ata neutral-line position, trigger slide plate ribs 52 f are in no stresscondition. The stress increases as the boss portion 52 c of the triggerslide plate 52 travels from the “HOME” position Q1 to the “TRIGGER”position Q3 through a “TRANSITION” position Q2. FIG. 10( b) shows a sideview of the trigger slide plate 52.

At the “TRIGGER” position Q3, the trigger slide plate 52 starts to pushtrays T to engage them with the tray driving gear unit 20. At end ofmoving sequence, the opening of the cam profile allows the boss portion52 c to release the stress trigger slide plate ribs 52 f and return tothe neutral condition. Thus, the boss portion 52 c of the trigger slideplate 52 can return to “HOME” position following the other path to avoidits profile overlapping with the trays T when the trays T return fromthe disc exchange position X to the standby position Y.

At the “HOME” position Q7, bending stress start to increase on thetrigger slide plate rib 52 f at the opposite direction (towards theleft). At a position Q8, the stressed trigger slide plate ribs 52 f isreleased after the trigger slide plate 52 moves to an opening on the camprofile and return to its origin position (“HOME” position).

FIGS. 11( a) to 11(c) show the engagement and disengagement of the traydriving gear unit 20 with a tray T. At an initial condition (when thetrays T are at standby position Y, before they are triggered by thetrigger slide plate 52), the gear rack Td is not engaged with the traydriving gear unit 20. After the trays T are triggered by the triggerslide plate 52, the trays T move forward and the gear rack Td willengage with the tray driving gear unit 20. Thus, all trays T will bedriven forward at the same time to the disc exchange position X.

For the return condition, the gear rack Td leaves the tray driving gearunit 20 when it reaches the standby position Y. The tray lock lever 53will be pushed away by trigger rib Th as shown in FIG. 12( b), at thetime that the last gear tooth of the gear rack Td leaves the traydriving gear units 20, and the tray lock lever 53 rotates into therecess of tray rib as FIG. 12( a). The contact of the locking profile 53a and a surface Tj of the recess create an inter-lock effect to preventtrays T from moving towards the disc exchange position X after reachingthe standby position Y. After all the trays reach to the standbyposition Y, the first protrusion 52 e of the trigger slide plate 52 willbe pushed to the lock lever rib 53 b and aligns and locks the trays T atthe standby position Y as shown in FIG. 9( a).

FIG. 13( a) is an exploded view of the tray driving gear unit 20. Thereference numeral 24 denotes a top tray drive gear which drives theupper most tray T1, the reference numeral 22 denotes a tray drive gearwhich drives trays T (T2-T4) other than the upper most tray T1 and thelower most tray T5, the reference numeral 25 denotes a bottom tray drivegear which drives the lower most tray T5. Further, the reference numeral23 denotes a plastic ring located between two drive gears adjacent toeach other which enables the drive gear 22, 24 or 25 to have a dummyturning, and the reference numeral 21 denotes a shaft gear fixed to ashaft 21 s which holds all drive gears 22, 24, 25 and the plastic rings23. Top drive gear 24 is fitted to the shaft 21 s in a tight fittingcondition and rotates as one solid body with it. FIG. 13( b) shows acomplete assembly of the tray driving gear unit 20. As seen from FIG.13( b), the plastic ring 23 is provided with stopper ribs 23 a, 23 b,the top tray drive gear 24 is provided with stopper ribs 24 a, 24 b.

FIG. 14 is a perspective view of the tray driving gear unit 20 and agear mechanism for driving it. As shown in FIG. 14, the shaft gear 21 ofthe tray driving gear unit 20 is engaged with a tray relay gear 112which is driven by the cam gear 114. When cam gear 114 rotates in aclockwise direction, the shaft gear 21 is driven to rotate in the samedirection. The top driving gear 24 also rotates in the same direction.

It is to be noted that a metal spring 26 having protrusions 26 a isprovided at a vicinity of tray driving gear unit 20. And, theprotrusions 26 a of the metal spring 26 are touching to side portions oftray drive gears 22 and 25, thereby friction force is provided to thetray drive gears 22 and 25 so that they are held in position before theyare driven by actual force from a electric motor 116 (described in moredetail below with reference to FIG. 21).

FIGS. 15( a) to 15(g) show a “RESET” operation of the tray driving gearunit 20. The “RESET” is to rotate all tray drive gears 22, 24 and 25with the same rotational speed, as if they were one solid gear which hasa plurality of layers of drive gears 22, 24 and 25 capable of engaging aplurality of trays T. In this explanation, only the top tray drive gear24 and the adjacent lower level tray drive gear 23 are explained becausethe “RESET” sequence for the following tray drive gears is the same.FIGS. 16 and 17 show the tray driving gear unit 20 after driving alltrays T to the standby position Y.

In order to drive the trays T to the disc exchange position X, the traydriving gear unit 20 needs to rotate in a clockwise direction in thedrawings. A tray relay gear 112 which is driven by the cam gear 114rotates to turn the shaft gear 21. Referring to FIGS. 14 and 15( a), asthe top tray drive gear 24 rotates together with the shaft 21 s in theclockwise direction, a side surface of the stopper rib 24 b on the toptray drive gear 24 will contact a side surface of the stopper rib 23 a(level 1) on the adjacent lower level plastic ring 23 after about 1round of rotation. Top tray drive gear 24 and the plastic ring 23 rotatetogether and continue the second rotation, until a side surface of thestopper rib 23 b (level 1) of the plastic ring 23 contacts to a sidesurface of the stopper rib 23 a (level 2) which is located 2 levelslower than top tray drive gear 24.

FIGS. 15( e) and 15(f) are the top and isometric views of the traydriving gear unit 20 without the top tray drive gear 24. When a stopperrib 23 a of the second level plastic ring 23 rotates, it touches thestopper rib 22 b on the next tray drive gear 22. This tray drive gear 22now will rotate in the same direction and speed with top drive gear 24.The rotation continues until the bottom tray drive gear 25 starts torotate, at this time the tray driving gear unit 20 is completely “RESET”as shown in FIG. 15( g). In this condition, all gear teeth are alignedwith each other and rotate as one solid body gear.

FIG. 16 is a side view of tray driving gear unit 20 with trays T atstandby position Y. And, FIG. 17 is an enlarged perspective view of traydriving gear unit 20 with trays T at standby position Y. As explainedabove, the metal spring 26 having protrusions 26 a is provided at avicinity of the tray driving gear unit 20. The protrusions 26 a of themetal spring 26 are touching side portions of the tray drive gears 22and 25, thereby friction force is provided to the tray drive gears 22and 25 so that they are held in position before they are driven byactual force from the motor 116.

FIGS. 18( a) to 18(d) show the operation of the tray driving gear unit20 for driving trays T to disc standby position Y, one by one from topto bottom. Top tray drive gear 24 tightly fitted to the shaft 21 s atthis time also starts to rotate among all tray drive gears.

In order to drive trays T from the disc exchange position X to thestandby position Y, the tray driving gear unit 20 needs to rotate in acounterclockwise direction in the drawings. This time, the side surfaceof the stopper rib 24 a after the first rotation will contact the sidesurface of the stopper rib 23 b (level 1) of the plastic ring 23,thereby the tray T is driven from the disc exchange position X to ahalf-way position between the disc exchange position X and the standbyposition Y, because number of plastic ring 23 used between the traydrive gears is two. The second rotation continues until the stopper rib23 a (level 1) contacts the stopper rib 23 b (level 2). Top tray T1 isnow completely driven to the standby position Y. The second tray T2 willstart to move when the stopper rib 23 a (level 2) rotates and pushes thestopper rib 22 b on the lower tray drive gear 22.

FIG. 19( a) is a plan view of the disc changer 1, where the top tray T1has been driven by the top tray drive gear 24 to the standby position Yand the second tray T2 is waiting for rotation of tray driving gear unit20 to move from the disc exchange position X to the standby position Y.FIG. 19( b) shows the tray driving gear unit 20 which engages with traysT. Top tray T1 moves to the standby position Y and disengages from thetray drive gear 22 and other lower level trays T are at the discexchange position X. Closing of trays T will be performed from top tobottom.

FIGS. 20( a) to 20(c) are side views showing a sequence of closing thetop tray T1 from the disc exchange position X to the disc standbyposition Y. FIG. 20( a) shows a state in which all trays T arepositioned at the disc exchange position X. It is to be noted that thetray driving gear unit 20 is to rotate as one body when it drives traysT to the disc exchange position X.

FIG. 20( b) shows a state in which the top tray T1 is closed to half waybetween the disc exchange position X and the disc standby position Y. Itis performed by a first rotation of the tray driving gear unit 20. FIG.20( c) shows a state in which the top tray T1 is fully closed to thedisc standby position Y. It is performed by a second rotation of thetray driving gear unit 20. Thereafter, the second tray T2 will start tomove, if the tray driving gear unit 20 continues to rotate.

The plastic rings 23 in this design are useful for reducing the size ofthe tray drive gears 22 by providing dummy rotation to the drive gears.A first tray drive gear will rotate to close a tray T just after thetray T disengages from the first tray drive gear, and a stopper rib ofthe first tray drive gear will hit a stopper rib of the plastic ring 23,so that a second tray drive gear is rotated. This means that the firsttray drive gear will rotate by a degree of (360−2θ) (where angle θ is anangle corresponding to a width of a stopper rib, as shown in FIG. 15( h)to drive the tray to disc standby position before the second tray drivegear starts to rotate to drive a second tray T2.

If there were no plastic rings 23, the PCD (pitch circle diameter) ofdrive gears of “D₁” for a tray ejection stroke of “y” would be given bythe formula (1).D ₁ =[y/π]×[360/(360−2θ)]  (1)

Since plastic rings 23 are used, the PCD (pitch circle diameter) ofdrive gears of “D₂” for a tray ejection stroke of “y” will be given bythe following formula (2). In this case, a tray ejection stroke of “y”will consist of a stroke achieved by a tray drive gear 22 and a strokeachieved by a plastic ring 23.y=πD ₂[(360−2θ)/360]+D ₂[(360−2θ)/360]=2πD ₂[(360−2θ)/360]D ₂=[1/2]×[y/π]×[360/(360−2)]D ₂=[1/2]D ₁  (2)Therefore, by using plastic rings 23 (dummy rings), the PCD of traydrive gear 22 can be reduced by ½.

If “n” pieces of plastic rings 23 were used (as they might be in otherembodiments of the invention), the PCD (pitch circle diameter) of drivegears of “Dn” for a tray ejection stroke of “y” would be given by thefollowing formula (3).y=πD ₂[(360−2θ)/360]+n{πD ₂[(360−2θ)/360]}=(1+n)πD ₂ [(360−2θ)/360]Dn=[1/(1+n)]×[y/π]×[360/(360−2θ)]Dn=[1/(1+n)]D ₁  (3)

With more plastic rings 23, the diameter of tray drive gear 22 can bereduced more.

Next, a driving mechanism of the disc changer 1 will be explained.

FIG. 21 is a plan view showing a total layout of a driving (gear)mechanism 100 in the disc changer 1 according to the embodiment. FIG. 22is a plan view showing the details of a main part of FIG. 21.

In FIGS. 21 and 22, a reference character Z denotes a discrecording/reproducing position, a reference character Y denotes a discstandby position and a reference character X denotes the disc exchangeposition. Also, a reference numeral 100 denotes a gear mechanism of thedisc changer 1 located at the disc standby position Y.

In FIGS. 21, 22 and 23, a reference numeral 116 denotes an electricmotor which provides driving power to the gear mechanism. The drivingmechanism 100 includes a motor pulley 115, a belt 121, a pulley gear101, a first relay gear 102, a second relay gear 103 and a third relaygear 104. The second relay gear 103 is provided on a back side of thepulley gear 101. The driving mechanism 100 also includes a switchinggear 105, a long gear 106, a function gear 107, a first UD gear 108, asecond UD gear 109, a first play gear 110 and a second play gear 111.Further, the driving mechanism 100 includes a main drive gear 113, a camgear 114 and a tray relay gear 112. All the drive gears are locatedinside the mechanical chassis 3.

FIG. 23 is a perspective view showing a gear engagement around aswitching gear 105. Switching gear 105 always engages to the third relaygear 104 and an up/down movement of the switching gear 105 is performedby sliding along the third relay gear 104. Each switching gear tooth 105a has a taper surface for easy engagement to a long gear 106 and a maindrive gear 113. The main drive gear 113 has a coining profile 113 a oneach gear tooth for easy engagement to the switching gear 105.

FIG. 24 is a perspective view showing a gear engagement around afunction gear 107. Function gear 107 always engages to the long gear 106and an up/down movement of the function gear 107 is performed by slidingalong the long gear 106. Each function gear tooth 107 b has a tapersurface for easy engagement to a first UD gear 108 and a first play gear110. The first play gear has a coining profile 110 a on each gear toothfor easy engagement to the function gear 107.

FIGS. 25( a) and 25(b) are schematic side views showing a first geartrain changing system by a switching gear 105. As shown in FIG. 25( a),the switching gear 105 is supported by a plunger lever 126. When anelectric current is applied to a plunger unit 117, the plunger unit 17pulls the plunger lever 126 by using a moving core 118, and in this waythe switching gear 105 will be lifted up to engage with the long gear106. On the other hand, when no electric current is supplied to theplunger unit 117, the switching gear 105 will be pushed down by a coilspring 119 and engaged with the main drive gear 113, as shown in FIG.25( b).

The operation of the driving mechanism 100 when the switching gear 105is at the lower position is to drive the functions of a tray open/closesystem or selection system (play/stock driving/elevation driving). Onthe other hand, the operation of the driving mechanism 100 when theswitching gear 105 is at the upper position is to drive the functions ofa tray play/stock system or an elevation system.

FIGS. 26( a) and 26(b) are schematic side views showing the second geartrain changing system by a function gear 107. As shown in thesedrawings, the function gear 107 is supported by a function lever 125.The round end portion 125 a of the function lever 125 moves following tothe outer profiles 114 e and 114 f at the lower side of the cam gear114. When cam gear 114 rotates and plan profile 114 e is touching theround end portion 125 a of the function gear 107, the function gear 107is lifted up by the function lever 125. At this time, the function gear107 is engaged with the first UD gear 108 which will drive the elevationsystem. FIG. 26( b) shows a flat surface 114 f of the cam gear 114touching the round end portion 125 a. In this state, the function gear107 is pushed down by the function lever 125, and the function gear 107is engaged with the first play gear 110 which will drive the trayplay/stock system.

FIG. 27 is a perspective view of a function lever 125 and a functiongear 107 of the disc changer 1 in an assembly condition. Function lever125 has a hook portion 125 b which holds a gear body 107 a of thefunction gear 107. With the configuration, function lever 125 can alwayshold the function gear 107, and the function gear 107 can move in avertical direction by a motion of the function lever 125.

FIG. 28( a) is a plan view showing a cam gear 114. And FIG. 28( b) is aperspective view showing the outer profiles 114 e and 114 f at the lowerside of the cam gear 114. As shown in FIG. 28( a), the gear teeth 114 aof the cam gear 114 are engaged with the main drive gear 113 and thetray relay gear 112. The cam gear 114 has cam grooves 114 b, 114 c and114 d to create the rotational movements of the trigger gear 51, thefirst lock lever 93 and the second lock lever 94.

The outer profile 114 e and 114 f at the lower side of the cam gear 114is used to change the state of function lever 125. The flat surfaceprofile 114 e allows the function gear 107 to engage to perform anelevation driving function and the flat surface profile 114 f allows thefunction gear 107 to engage to perform a tray play/stock function. Thecam gear 114 also has a sensor profile 114 g for sensing changes ofelectronic sensor signal for indicating the tray T condition whenopening or closing.

In order to achieve single motor driving, the driving mechanism 100 ofthe disc changer 1 has a switching mode as explained by a block diagramshown in FIG. 29. Power supplied from electric motor 116 is directed tothe different gear train systems (an elevation system, a tray play/stocksystem and a tray open/close system) by using the switching gear 105 andthe function gear 107. The level of both gears is changed by using theplunger unit 117 and the flat surface profiles 114 e and 114 f of thecam gear 114.

FIG. 30 is a plan view showing a gear train of a tray open/close systemin the disc changer 1. This gear train drives trays T between the discexchange position X and the disc standby position Y.

When the disc changer 1 operates to drive the gear train of trayopen/close system, a driving source gear train will connect to the maindrive gear 113. The driving source gear train is to connect the drivingsource from the electrical motor 116 all the way until the switchinggear 105. The gear train is from cam gear 114, tray relay gear 112 andthen to tray driving gear unit 20 through a shaft gear 21. The traydriving gear unit 20 is designed such that it can drive all trays T fromthe standby position Y to disc exchange position X at once.

FIGS. 31( a) to 31(d) are plan views showing the sequence of trayopening operations which are mainly controlled by cam gear 114. The trayopen/close system includes the triggering section 50 and tray drivinggear unit 20. The triggering section 50 comprises a trigger gear 51, atrigger slide plate 52 and a tray lock lever 53. When the disc changer 1is operated to drive the tray open/close system, the cam gear 114rotates in clockwise direction to move a tray T to disc exchangeposition X (open), or rotates in counter clock-wise to move a tray T todisc standby position Y (close). In the case of opening the trays T, atthe time the cam gear 114 rotates, the tray driving gear unit 20 rotatesto “RESET” all the drive gears in order to rotate as one body, and thecam profile 114 b at the same time pushes the trigger gear 51 to rotateto drive the trigger slide plate 52.

FIG. 31( a) shows the state at the instant that the tray open/closesystem starts to move. The tray lock lever 53 in this state locks alltrays T and tray drive gear unit 20 is not engaged with the trays T.FIGS. 31( b) and 31(c) show states in which the cam gear 114 is beingdriven by the gear train of tray open/close system and the rotation ofthe cam gear 114 will move the trigger slide plate 52 through a triggergear 51. During the movement of the trigger slide plate 52, it unlocksthe tray lock lever 53 to release the trays T. FIG. 31( c) shows a statein which the trays T are pushed to engage the tray driving gear unit 20.FIG. 31( d) shows a state in which all trays T are driven to the discexchange position X by the tray driving gear unit 20. The tray T closingis done by reversing the tray opening operation. Trays T will close oneby one from top to bottom.

FIGS. 32( a) and 32(b) are perspective views showing the trigger gear 51and the trigger slide plate 53. In the state shown in FIGS. 32( a) and32(b), a boss 51 a (see FIG. 7) of trigger gear 51 is inserted into acam groove 114 b of cam gear 114 and driven by a profile of the camgroove 114 b. The cam groove profile 114 b on cam gear 114 is thecontrol path for the trigger gear 51 movement. Gear teeth 51 b ontrigger gear 51 constantly engage a rack gear 52 b of the trigger slideplate 52. The trigger gear 51 rotates around its supporting boss 51 cwhich is held by a boss 120 a of a pitch plate 120. A boss 51 a of thetrigger gear 51 is moved by the cam groove 114 b. Thus, when the camgear 114 rotates, a motion of cam groove 114 b is transmitted to thetrigger slide plate 52 by trigger gear 51 and allows the trigger slideplate 52 to move in a linear way.

FIG. 33 is a plan view showing a gear train of an elevation system inthe disc changer 1. This gear train operates in order to move therecording/reproducing section 70 in vertical direction and then align itto specific a tray T.

When the disc changer 1 is operated to drive the gear train of theelevation system, the driving source gear train transfers the drivingsource from electrical motor 116 to a long gear 106, a function gear107, a first UD gear 108 and a second UD gear 109. The driving sourcegear train transfers the driving source from electrical motor 116 to allthe way until switching gear 105. The gear train of the elevation systemthen will drive an elevating unit 30 for moving therecording/reproducing section 70 in vertical direction.

FIG. 34 is a perspective view showing the components of the elevationunit. A right side UD rack 32 and a left side UD rack 31 are connectedto each other by one connection lever 33. The elevation unit is used tomove the recording/reproducing section 70 in a vertical direction byconnecting to the gear train of the elevation system. The driving sourceis transferred by gear teeth 109 a of a second UD gear 109 to a gearrack 32 b of the right side UD rack 32. There is a step-like cam 32 aand 31 a on each UD rack 32 and UD rack 31. The step-like cams 32 a, 31a have a cam profile similar to steps in a side view.

The cam profiles of the step-like cams 32 a and 31 a direct the movementof the recording/reproducing section 70. The bosses 5 a provided on theside of a UD base 5 sit in the cam profile 32 a, 31 a of UD racks 32, 31and they are supported by left guides 3 b and a right guide rib 3 c ofthe mechanical chassis 3. When the UD racks 32, 31 are moving linearlyforward or backward, the recording/reproducing section 70 moves invertical direction. UD rack 32 is connected to UD rack 31 to createsynchronous movement by means of the connection lever 33. A boss 32 c ofthe right side UD rack 32 is fitted into a slot 33 a of the connectionlever 33. Also, a boss 31 b of the left side UD rack 31 is fitted into aslot 33 b of the connection lever 33 on the opposite side.

FIG. 35 is a side view showing the step-like cam profile 32 a on theright side UD rack 32. The step-like cam 32 a has horizontal portions 32a-1 to 32 a-5 which correspond to the positions or levels of therecording/reproducing section 70 that align to tray T. The level of 32a-1 to 32 a-5 is determined by an electrical sensor using the sensorprofile 32 d.

FIGS. 36( a) and 36(b) are perspective views respectively showing therecording/reproducing section 70 at an upper most position (for tray T1)and an lower most position (for tray T5). For elevating therecording/reproducing section 70 to the upper position, the right sideUD rack 32 is driven by the gear train of elevation system in theforward direction. This movement will be transferred, by the connectionlever 33 supported pivotally by the boss 120 b of the pitch plate 120,to the left side UD rack 31. Consequently, the left side UD rack 31 willmove in the rear direction. For moving the recording/reproducing section70 to the lower position, the moving direction of both UD racks 32, 31are opposite to the above.

FIG. 37 is a plan view showing a gear train of the tray play/stocksystem in a disc changer 1. This gear train drives trays T between thedisc recording/reproducing position Z and the disc standby position Y.

When the disc changer 1 operates the drive gear train of the trayplay/stock system, the driving source gear train transfers the drivingsource from electrical motor 116 to a long gear 106, a function gear107, a first play gear 110 and a second play gear 111. The gear train ofthe tray play/stock system then will drive a tray driving rack unit 60which is capable of moving trays T between the recording/reproducingposition Z and the disc standby position Y.

FIGS. 38( a) and 38(b) are plan views showing the movement of drivingtrays T between the disc standby position Y and therecording/reproducing position Z.

After the recording/reproducing section 70 is aligned to a selected trayT level, the tray T can be driven between the disc recording/reproducingposition Z and the disc standby position Y by the tray driving rack unit60.

FIG. 39 is a perspective view showing the components of the tray drivingrack unit 60. The tray driving rack unit 60 has a tray catch lever 61, afirst play lever 62, a second play lever 63, a tray drive rack 64 and atransverse slide plate 65. When there are no trays T at therecording/reproducing position Z and all trays T are at the standbyposition Y, the gear train of tray stock/play system is connected by thesecond play gear 111 to the tray drive rack 64 through the gearengagement of a rack gear 64 a and gear teeth 111 a of the second playgear. When the second play gear 111 rotates in the clock-wise direction,tray T is driven to recording/reproducing position Z.

FIGS. 40( a) to 40(d) are enlarged plan views showing a moving sequenceof the tray catch lever 61 to drive trays T from the disc standbyposition Y to the recording/reproducing position Z. FIG. 40( a) shows astate in which the tray catch lever 61 is away from tray T at discstandby position Y. The UD base 5 supports the tray catch lever 61moving in a vertical direction to align tray T which needs to be drivento the recording/reproducing position Z.

As the tray drive rack 64 moves backward when the second play gear 111rotates in clock-wise direction as shown in FIGS. 40( b) and 40(c), theboss 64 b on tray drive rack 64 pulls the tray catch lever 61 throughthe hole 61 a. As the tray catch lever 61 moves backward, the catchprofile (concave portion) 61 b rotates to fit into hook profile Tg ofthe tray T. The rotation of tray catch lever 61 is due to the cam groove61 c on the lower surface of tray catch lever 61 and a small boss 5 b onUD base 5. The rotation of tray catch lever 61 is caused by the camgroove 61 c fitting against the small boss 5 b. Further, tray T will bemoved to the disc recording/reproducing position Z by the tray drivingrack unit 60 as shown in FIG. 40( d).

FIGS. 41( a) to 41(d) are enlarged plan views showing a sequence of anoperation of the tray driving rack unit 60. FIG. 41( a) shows an initialposition when the tray drive rack 64 and the tray catch lever 61 arepositioned for driving trays T in the disc standby position Y. In thisstate, the second play gear 111 engages the rack gear 64 a of tray driverack 64, and the rack gear 65 b of transverse slide plate does notengage the second play gear 111. FIG. 41( b) shows a boss 64 c of thetray drive rack 64 moved into an opening 63 a of the second play lever63 before the end of movement of tray drive rack 64. When tray driverack 64 continues to move backward, the second play lever 63 will bepushed by the boss 64 c of tray drive rack 64 and rotates, the boss 63 bof the second play lever 63 pushes the opening 62 a of the first playlever 62.

Further, a boss 62 b of the first play lever 62 which is inserted into acam profile 65 c of the transverse slide plate 65 rotates and pushes thetaper surface of the cam profile 65 a. Transverse slide plate 65 ispushed to move to right side and the first gear tooth of the rack gear65 a will engage the gear teeth 111 a of the second play gear 111 asshown in FIG. 41( c). The driving source will now be transferred to thetransverse slide plate 65, and this slide plate 65 is driven to rightside until it detects a switch that marks the completion of discclamping operation as shown in FIG. 41( d).

For driving a tray from disc recording/reproducing position Z to discstandby position Y, the operation is the reverse of the above. Thedriving source will be transferred from the second play gear 111 totransverse slide plate 65. The cam profile 65 a of the transverse slideplate 65 triggers rotational motion of the first play lever 62, and thenthe second play lever 63 which will pull the tray drive rack 64 toengage to the second play gear 111. Tray drive rack 64 will pull traycatch lever 61 that hook to tray T. When tray T reaches the disc standbyposition Y, the tray catch lever 61 will come out from tray profile Tgand rotates in a counter clock-wise direction back to its originalposition. The rotation is same achieved by cam groove 61 c and the boss5 b of the UD base boss 5 as shown in FIG. 40( b)

FIGS. 42 and 43 are side views respectively showing clamper unit 10 inunclamping and clamping conditions. The transverse unit 6 in the discrecording/reproducing unit section 70 is supported by UD base 5 andtransverse slide plate 65. Two of the side bosses 6 a at the rear sideof the transverse unit 6 are mounted to hook profiles. And bosses 6 b atthe front side of the transverse unit 6 (refer to FIG. 39) are mountedinto the cam profile 65 c of transverse slide plate 65 (refer to FIG.39). With the pivot at rear side, the transverse unit 6 will rotate to aclamping position when the transverse side plate 65 moves from the leftside to the right side, and to a unclamping position when transverseside plate 65 moves from the right side to the left side.

At the time of clamping, a clamper support plate 11 is pushed downwardto a turn table 9 in order to place the clamper unit 10 to the turntable 9. With the lifting of clamper unit 10 by clamper support plate 11at the time of unclamping, tray T can have more gap when it moves torecording/reproducing position Z. The movement of clamper support plate11 is controlled by the movement of bosses 6 b of the transverse unit 6.

In the unclamping condition, a rib 6 c of the transverse unit 6 touchesa rib 11 a of the clamper support plate 11. The clamper support plate 11is lifted away from the turn table 9 and clamper unit 10 is at its upperposition. In the clamping condition, the other side of the rib 6 c ofthe transverse unit 6 touches the other side of the rib 11 a of clampersupport plate 11. This brings down the clamper support plate 11 and alsoclamper unit 10. The clamper unit 10 now is sitting on turn table 9 andable to rotate freely with the turn table 9.

FIG. 44 shows a locking system for trays T at the disc standby positionY. The locking system uses a triggering system 50 that consists of atrigger gear 51, a trigger slide plate 52 and tray lock levers 53.

FIGS. 45( a) and 45(b) are respectively a top view and an isometric viewof the tray lock levers 53. Each tray lock lever 53 includes a firstprotrusion 53 a, a stopper rib 53 b, a second protrusion 53 c and aplastic spring 53 d. The first protrusion 53 a provides an“inter-locking” effect to tray T. The stopper rib 53 b is to ensure astable locking state to tray T. The second protrusion 53 c is a profilewhich is used to unlock the tray T from the tray lock lever 53. Theplastic spring 53 d is to provide a spring effect to the tray lock lever53, and to ensure that the position of the first protrusion 53 a iscorrect, in order to create a stable locking effect when the stopper rib53 b is not touching a locking profile of the trigger slide plate 52.

The lock/unlock operation is carried out simultaneously in a traytriggering and opening operation. It can be referred to as part of theoperation to drive a tray T to the disc exchange position X.

FIG. 46 (discussed in more detail below) is a diagram showing arelationship between cam gear 114 positions and locking types of thetray T. FIG. 47( a) to 47(c) are enlarged plan views showing tray locklevers 53 in locking trays T at standby position Y. FIG. 48 is aperspective view of the disc changer from the front side in a state inwhich the trays are locked at the standby position Y. The trays T at thestandby position Y are locked by tray lock lever 53 from going to frontposition (disc exchange position X) at any time of operation except whentrays T are driven to the disc exchange position X (open trayoperation). This is a shipment locking position where the trays arelocked in a permanent manner at the disc standby position Y, and thedisc changer 1 at all times carries out operations to lock tray T at theshipment locking position after any operation (such as driving tray Tbetween disc standby position Y and disc recording/reproducing positionZ or driving the recording/reproducing unit 70 moving up/down to selecttray T).

In other states, the trays T are in held in the locking condition by the“inter-locking” profile of tray T and the tray lock lever 53. FIG. 46shows a timing chart when the cam gear 114 rotates from “HOME” positionto disc exchange position X and types of locking condition of the traylock lever 53 and trigger slide plate 52. For type A shown in FIG. 47(a), the first protrusion 53 a of tray lock lever 53 is being pushedtoward the surfaces Tk and Tm of the tray T by the first protrusion 52 eof the trigger slide plate 52. This creates a strong stable lockingcondition in which the trays T cannot move to any position. For type Bshown in FIG. 47( b), the trigger slide plate 52 moves toward the frontside and the first protrusion 52 e of the trigger slide plate 52 is awayfrom the first protrusion 53 a of tray lock lever 53, so the locking isonly by “inter-locking” between tray T and tray lock lever 53.

The plastic spring 53 d is touching a wall of mechanical chassis 3 andtray lock lever 53 is not able to rotate to unlock direction. At thistime, the trays T are not able to move to the front side (disc exchangeposition X) but the tray T which is aligned to the tray catch lever 61(the selected tray T to be driven to recording/reproducing section 70)can move to the rear side (disc recording/reproducing position Z) if itis pulled by tray driving rack unit 60. Regarding to the other trays T,they are blocked by either tray rear stopper 95 or a wall of UD basewall as shown in FIG. 48. An unlock period only happens before the traysT triggering, when the tray lock lever unlock profile 53 c is beingpushed by the second protrusion 52 d of the trigger side plate 52 andthe tray is unlocked for a short period so that it can be pushed bytrigger slide plate 52 to engage with the tray driving gear unit 20.

FIG. 49 is a perspective view of the disc changer 1 from the rear sidein a state in which the trays T are locked at the stand by position Y.The recording/reproducing section 70 and tray catch lever 61 are alignedto the tray T3, and in this state the trays T1, T2 are locked in standbyposition Y by tray lock lever 53 and tray rear stopper 95. Trays T4 andT5 are locked in the standby position Y by tray lock lever 53 and UDbase wall and rib 5 d. The rear side of selected tray T3 is stopped by aconcave portion 61 b of the tray catch lever 61. When tray catch lever61 is rotated and the concave portion 61 b goes into tray hook portionTg, the tray T3 can be driven to the disc recording/reproducing positionZ.

FIG. 50 is a plan view showing the locking system at therecording/reproducing section 70. One portion of the locking system isfor the transverse unit 6 and the tray driving rack unit 60, and anotherportion of the locking system is for the recording/reproducing section70. The locking system is to ensure that the disc changer 1 can sustainexternal vibration and impact which can cause the disc changer 1malfunction while transportation or mishandling. The locking systemensures that there is no position shift and dislocation of parts, byholding each part securely with a locking device. The locking deviceused to achieve this function is a first lock lever 93 for locating thetransverse unit 6 and tray driving rack unit 60, and a second lock lever94 for locking the whole recording/reproducing section 70.

Both of lock levers 93, 94 are controlled by cam grooves 114 c, 114 d ofthe cam gear 114 and pivot on pitch plate boss. One end of both locklevers 93, 94 have bosses that insert into the cam grooves 114 c, 114 dand the other end have special locking protrusions that create maximumlocking effect when they engage the profile on a second play gear 111and a second UD gear 109.

FIGS. 51( a) and 51(b) are perspective views showing a first lock lever93 and a second play gear 111 in a locking condition. A hook portion 93a of the first lock lever 93 engages with a gear tooth 111 a of thesecond play gear 111 to lock the tray play/stock gear train. A taperprofile 93 c on the hook portion 93 a of the first lock lever 93 and ataper profile 111 c on the gear tooth 111 a of the second play gear 111create an inter-locking effect. These configurations provide a stronglocking condition to the tray play/stock system gear train.

FIGS. 52( a) and 52(b) are a plan view and a perspective view showingthe first lock lever 93 as a locking device of the disc changer 1 in twoconditions. These drawings show the first lock lever 93 in a state wherea hook portion 93 a of the first lock lever 93 engages with a gear tooth111 a of a second play gear 111, thereby locking the second play gear111. At this time, gear teeth 111 a are engaged with a rack gear 64 a ofa tray drive rack 64. This condition will happen when the tray driverack 64 is at standby position Y and no trays T are at discrecording/reproducing position Z.

FIGS. 53( a) and 53(b) are a plan view and a perspective view showingthe first lock lever 93. These drawings also show the first lock lever93 in a state where a hook portion 93 a of the first lock lever 93engages with a gear tooth 111 a of the second play gear 111, therebylocking the second play gear 111. At this time, gear teeth 111 a engagea rack gear 65 a of a transverse slide plate 65. This condition willhappen when the tray drive rack 64 drives a tray T to the discrecording/reproducing position Z and the transverse slide plate 65 movesto clamp the disc to conduct disc recording/reproducing.

FIG. 54( a) is a plan view showing a locking state of the first locklever 93. In this condition, a boss 93 b of the first lock lever 93 fitsinto a cam gear groove 114 c located in a first range 114 c-1 of the camgear groove 114 c where the first lock lever 93 is directed to rotate ina lock direction. FIG. 54( b) is a plan view showing an unlockingcondition of the first lock lever 93. In this condition, the boss 93 bis located at a second position 114 c-2 of the cam gear groove 114 cwhere the first lock lever 93 is directed to rotate in an unlockdirection. There is only one portion 114 c-2 on cam gear groove 114 c,where the same position is used to change the state of function lever125.

FIG. 55 is a perspective view showing a state of the locking system inwhich the cam gear 114 rotates to a position for unlocking the firstlock lever 93. In this state, the position of a function lever 125 ischanged in order to drive a gear train of a tray play/stock system (atray driving rack unit).

FIG. 56 is a plan view showing a second lock lever 94 as a lockingdevice in the disc changer 1. In the state shown in FIG. 56, a protrudedportion 94 a of the second lock lever 94 engages a locking profile 109 bof a second UD gear and locks the second UD gear 109. At this time, gearteeth 109 a engage a rack gear 32 b of UD rack 32. This condition willhappen after the recording/reproducing section 70 complete the up/downmovement to select a tray T for driving to the recording/reproducingposition Z.

FIG. 57 is a perspective view showing the second lock lever 94 and thesecond UD gear 109 in an unlocked condition. A protruded portion 94 a ofthe second lock lever 94 enters into a locking profile 109 b of thesecond UD gear 109 to lock the elevation gear train. The second UD gear109 has a taper portion 109 c for reliable engagement with the protrudedportion 94 a of the second lock lever 94 and alignment of the second UDgear 109.

FIG. 58( a) is a plan view showing a locking state of the second locklever 94. In this state, a boss 94 b of the second lock lever 94 fitsinto a cam gear groove 114 d located at a first range 114 d-1 of the camgear groove 114 d where the second lock lever 94 is directed to rotatein a lock direction. FIG. 58( b) is a plan view showing an unlockingstate of the second lock lever 94. In this state, the boss 94 b islocated at a second position 114 d-2 of the cam gear groove 114 d wherethe second lock lever 94 is directed to rotate in an unlock direction.There is only one portion 114 d-2 on cam gear groove 114 d, where thesame position is used to change the state of function lever 125.

FIG. 59 is a plan view of a cam gear 114 explaining an operation thereofwhen it rotates in a clockwise and a counter-clockwise direction.Rotational motion of the cam gear 114 starts from a HOME position, andthe cam gear 114 will rotate in a clock-wise direction to RESET the traydriving gear unit 20 in position A. The trays T do not move during thisoperation. From the HOME position, the cam gear 114 rotates in theclockwise direction to a PLAY DRIVING position to change the level offunction lever 126 from a level for engaging to a first UD gear 108 to alevel for engaging a first PLAY gear 110. From the PLAY DRIVING positionto the HOME position, the operation is reversed. In a range of positionsB, the trigger slide plate 52 triggers the trays T to engage to the traydriving gear unit 20. And in a range of positions C, trays T are drivento the disc exchange position X. When the cam gear 114 rotates in acounter-clockwisedirection, the tray T1 is first driven to the discstandby position Y in the range of positions C, and it will be followedby trays T2 to T5 in order.

FIG. 60 is a perspective view showing a state in which the cam gear 114is rotated to a position for unlocking the second lock lever 94. In thisstate, a position of the function lever 126 is changed in order to drivethe gear train of elevation system (elevation unit).

FIG. 61 is a perspective view showing another locking system thatprevents a movement of the recording/reproducing section 70 when one ofthe trays T is at the recording/reproducing position Z. The lockingsystem can protect the disc changer 1 from external shock and vibrationif there is an illegal power off during a recording/reproducingoperation. At the right side of transverse slide plate 65, there isprovided a pin 65 d which is capable of going into any of holes 32 e-1to 32 e-5 of the UD rack 32. The holes 32 e-1 to 32 e-5 correspondrespectively to the recording/reproducing positions that align tray T1to tray T5. With this configuration, recording/reproducing is locked ata current recording/reproducing tray T position.

FIG. 62 is a locking system summary table for the recording/reproducingsection 70. At all times, there is a lock system that is activated tolock the recording/reproducing section 70.

According to the configuration of the preferred embodiment of theinvention, the tray driving gear unit 20 is capable of driving the traysT from the standby position Y to the disc exchange position X with anall-at-once operation. At this time all tray driving gears of the traydriving gear unit 20 rotate in a tray opening direction as one solidgear for driving the plurality of trays T. Further, when the traydriving gear unit 20 rotates in an opposite direction the trays T aredriven one by one from the top tray to the bottom tray. Thus, it ispossible to eject all trays T at once, and exchange all discs D from thetop tray to the bottom tray. This simplifies the operation of exchangingall discs D in the disc changer 1. While all the trays T are protruding,all the discs D can be checked, and exchanged if necessary. The sametray driving gear unit 20 is commonly used for both shuttling the traysT between the standby position Y and the disc exchange position X anddisc checking function, thereby it is possible to simplify the design ofthe tray driving gear unit 20, simplify the disc changer operation,shorten the changing time and reduce the possibility of tray jams.

Further, according to the embodiment, the tray driving gear unit 20 iscapable of driving all trays T other than a tray T1 above therecording/reproducing unit 70 from the standby position Y to the discexchange position X with an all-at-once operation. At this time all traydriving gears of the tray driving gear unit 20 rotate in a tray openingdirection as one solid gear for driving all trays T except the tray atthe recording/reproduction position since that tray is not triggered bythe trigger slide plate. Further, when the tray driving unit 20 rotatesin an opposite direction the trays T are driven one by one from the toptray to the bottom tray. Thus, it is possible to eject all trays T otherthan a tray T above the recording/reproducing unit 70 at once, andexchange all discs D other than the disc D on the tray T above therecording/reproducing unit 70 from top tray to bottom tray. Thissimplifies the sequence for exchanging all discs D other than this trayT above the recording/reproducing unit 70 in the disc changer 1. Whileall but one of the trays T are protruding, all the discs D on thosetrays T can be checked. The same tray driving gear unit 20 can becommonly used for both shuttling the trays T between the standbyposition Y and the disc exchange position X and disc checking function,thereby it is possible to simplify the design of the tray driving gearunit 20, simplify the disc changer 1 operation, shorten the changingtime and reduce the possibility of tray jams.

Furthermore, according to the embodiment, the tray driving gear unit 20has a series of tray drive gears and can rotate to the RESET condition,and the trays T at the standby position Y are engage with the traydriving gear unit 20 by the tray triggering unit 50 after the traydriving gear unit 20 rotates to RESET condition. Thus, for each exchangeof the disc D, the trays T protrude to the disc exchange position X andreturn to the standby position Y one by one from top to bottom. Thissimplifies the operation of exchanging all discs D, since it is possibleto put a disc D onto any of the empty tray T without opening the traysone by one.

Still further, according to the embodiment, the tray drive gears(including top tray drive gear 24, tray drive gear 22 and bottom traydrive gear 25) are separated from the shaft gear body (made up of theshaft gear 21 and the shaft 21 s), therefore the tray driving gear unit20 can be manufactured much more easily in comparison with a prior artbody construction.

Still further, according to the embodiment, the tray drive gears areseparate from the shaft gear body, therefore the tray driving gear unitcan be manufactured much more easily in comparison with one bodyconstruction. Further, a top level tray drive gear fixed to the shaftgear body rotates as one body therewith at all times, and the rotationalmovement of the top level tray drive gear is transferred to the lowerlevel drive gear through the stopper ribs thereof. Thus, all tray drivegears are driven to rotate one by one through the stopper ribs.

Still further, according to the embodiment, the additional rotation isprovided to each tray drive gear by at least one spacer ring 23 placedbetween two tray drive gears adjacent to each other. The spacer ring 23can acts as a dummy gear in the rotational movement of the tray drivinggear unit 20, and can reduce the size of the tray drive gear, because,in a case that the tray driving gear unit 20 does not have a spacer ring23, the drive gear pitch diameter needs to provide a total circumferenceequivalent to a total stroke for one complete rotation, and thisincreases the diameter of the tray drive gear.

Still further, according to the embodiment, an upper level tray drivegear's stopper rib pushes a lower level tray drive gear's stopper rib,through the spacer ring's stopper ribs, in a rotational direction of theupper level tray drive gear, and the lower level tray drive gear isforced to rotate in the rotational direction of the upper level traydrive gear. Thus, the rotational movement of the top level tray drivegear is transferred to the lower level drive gear through the stopperribs, and all tray drive gears are driven to rotate one by one throughthe stopper ribs. Specifically, the size in a rotational direction ofthe stopper ribs is designed to equivalent to a multiple of gear teethpitching angle, therefore the stopper ribs can contact to each other ina more stable way.

Still further, according to the embodiment, it is possible to providethe tray driving gear unit 20 with a dummy turn which is equivalent tothe total stroke for moving a tray from the disc exchange position tothe standby position, thereby the size of the tray drive gear can bereduced.

Still further, according to the embodiment, the first gear tooth of thetray's gear rack has a shape profile for easy engagement of trays T totray driving gear unit 20 after triggered by the tray triggering unit50.

Still further, according to the embodiment, owing to the shape profileof the first gear tooth of the tray's gear rack, the tray's gear rackcan be easily engaged with the tray driving gear unit 20 after it istriggered by the tray triggering unit 50. Thereby, the tray T can startto move smoothly by the tray driving gear unit 20.

Furthermore, according to the preferred embodiment, the triggering slideplate 52 in the disc changer is controlled and activated by the cam slotof the cam gear 114, where the cam gear 114 is also used for drivingtrays. The triggering slide plate 52 pushes against tray lock lever 53and provides a strong stable lock to all the trays T at standby positionY. When the cam gear 114 rotates in a tray T opening direction, thetriggering slide plate 52 moves and the lock/unlock profile on the platewill push against the tray lock lever 53 in the unlock direction, at thesame time trigger profiles on the plate bend follow the slot onmechanical chassis 3 to push trays T move forward. Thus, it is possibleto common use a triggering slide plate 52 to open and lock trays T. Thetime for tray T unlocking is short as the triggering slide plate 53unlocks trays T just before pushing the trays to engage the tray drivinggears. This minimizes the tray T unlocking period before each tray T isdriven.

As the triggering slide plate 50 is being moved forward, the triggerprofile on the flexible ribs of triggering slide plate 50 will overlapwith the trays trigger rib, and push the trays toward the disc exchangeposition X. This creates an advantage that the trays T are largelyseparated in the standby position Y, not linked to any other part thanthe housing and the locking profile. This prevents any problem if thepositions of the trays T are slightly shifted at the shipment position.Upon, being triggered and pushed, the trays T can engaged with the traydriving gears for further transfer of trays T to the disc exchangeposition X or there can be a purely pushing action by triggering slideplate 52 itself if the stroke allows for the trays T to move fromstandby position Y to disc exchange position X. This creates anotheradvantage for the flexibility in creating various options of traydriving system.

Further, according to the embodiment, the triggering slide plate'strigger profile bend follows the cam profile on mechanical chassis 3.The profile changes while it moves from rear to front of the discchanger 1. The profile contacts the trigger rib on trays T at the traystrigger zone, trays T then being pushed forward to engage the traydriving gear unit 20. The trigger profile is formed on the triggeringslide plate 52 as one body to reduce cost, and the trigger profile ismore flexible to be bent and to withstand the trays triggering force.Pitching between the tray trigger rib and the triggering slide platetrigger lever profile can be controlled accurately.

In the embodiment, the guide slots on the mechanical chassis 3 can bearranged to have various heights and slopes. As the triggering slideplate 52 is being moved from standby position Y or shipment position tothe front, before the disc exchange position X, the cam profile ontriggering slide plate 52 is moved to the front and away from the traylock lever's flexible ribs. The tray lock lever's lock profile willprovide an interlock effect with the trays T. Triggering slide platelock/unlock profile pushes against the lock lever profile to get abetter locking effect at shipment condition. The plastic spring on thelock lever pushes against mechanical chassis 3 wall to provide atemporary locking effect to trays T while the trays T are entering fromdisc exchange position X to standby position Y.

Further, tray unlock period is minimized and the lock is immediate aftereach tray T is moved to standby position Y. The interlocking effect oftrays T can achieve the most effective locking result. When the tray Tmoves in the forward direction, the tray lock lever 53 rotates in thelocking direction and creates more locking force. In the shipment lockcondition, the tray lock lever 53 is not able to move as the triggeringslide plate lock profile minimizes the free play gap for tray lock lever53. So this only allows the trays T to move backwards into discrecording/reproducing position Z and prevents them from moving in theforward direction unless by means of pushing by the triggering slideplate 52.

Furthermore, the tray lock lever 53 is linked by plastic linkage tocreate a joining part that can rotate by itself without interfering withthe other levers while tray T passes over the lever to the stockingposition. Tray lock lever 53 with plastic linkage joins the separatelevers into one part for cost reduction and simplifies the mountingprocess. Tray lock lever 53 can act as separate 5 parts where therotation of each lever does not affect the other lever.

Industrial Applicability

The present invention is applicable to a disc changer, particularly to adisc changer that stores a plurality of discs therein, transports a discselected from a plurality of discs, and performs recording and/orreproducing information signal on the disc.

The invention claimed is:
 1. A disc changer for storing a plurality ofdiscs, transporting a disc selected from the plurality of discs, andperforming recording/reproducing of an information signal on the disc,the disc changer comprising: a plurality of trays which respectively canbe loaded with discs, can be moved substantially in a horizontaldirection parallel to main surfaces of the discs, and are stackedsubstantially in a vertical direction perpendicular to the main surfacesof the discs; a tray driving gear unit which has a plurality of drivinggears capable of respectively engaging with a rack provided on eachtray, such that the tray driving gear unit is capable of shuttling thetrays between a standby position in which the trays are stored in amechanical chassis as a housing of the disc changer and a disc exchangeposition in which the trays are protruded outward from the mechanicalchassis such that the discs can be put on the trays and removed from thetrays; a gear driving mechanism driven by an electrical motor togenerate a driving force for driving the tray driving gear unit; a traytriggering unit capable of locking/unlocking the trays in the standbyposition, the tray triggering unit being capable of pushing all trays ata same time so as to engage the rack provided on each tray with arespective driving gear of the tray driving gear unit after unlockingthe trays; a recording/reproducing unit for recording and/or reproducingan information signal on a disc placed on a turntable; and an elevationunit capable of moving the recording/reproducing unit with the turntablein the vertical direction to align the recording/reproducing unit to atray and place a disc on the tray onto the turntable, wherein the traydriving gear unit is configured such that, in a tray opening operation,the rack provided on each tray is engaged with a respective driving gearas the trays are pushed by the tray triggering unit, and all drivinggears are driven at a same time as one body such that the tray drivinggear unit moves all trays to protrude outward from the mechanicalchassis to the disc exchange position at a same time, and wherein thetray driving gear unit is configured to, in a tray closing operation,individually and sequentially move the driving gears engaged with therespective racks from top to bottom, such that the tray driving gearunit is capable of individually and sequentially driving the trays fromthe disc exchange position to the standby position from top to bottom inthe tray closing operation, whereby each disc on a topmost tray existsat the disc exchange position in the tray closing operation such thatthe disc on the topmost tray can be checked until the topmost tray isclosed.
 2. A disc changer for storing a plurality of discs, transportinga disc selected from the plurality of discs, and performingrecording/reproducing of an information signal on the disc, the discchanger comprising: a plurality of trays which respectively can beloaded with discs, can be moved substantially in a horizontal directionparallel to main surfaces of the discs, and are stacked substantially ina vertical direction perpendicular to the main surfaces of the discs; atray driving gear unit which has a plurality of driving gears capable ofrespectively engaging with a rack provided on each tray, such that thetray driving gear unit is capable of shuttling the trays between astandby position in which the trays are stored in a mechanical chassisas a housing of the disc changer and a disc exchange position in whichthe trays are protruded outward from the mechanical chassis such thatthe discs can be put on the trays and removed from the trays; a geardriving mechanism driven by an electrical motor to generate a drivingforce for driving the tray driving gear unit; a tray triggering unitcapable of locking/unlocking the trays in the standby position, the traytriggering unit being capable of pushing all trays at a same time so asto engage the rack provided on each tray with a respective driving gearof the tray driving gear unit after unlocking the trays; arecording/reproducing unit for recording and/or reproducing aninformation signal on a disc placed on a turntable; and an elevationunit capable of moving the recording/reproducing unit with the turntablein the vertical direction to align the recording/reproducing unit to atray and place a disc on the tray onto the turntable, wherein the traydriving gear unit is configured such that, in a tray opening operation,the rack provided on each tray is engaged with a respective driving gearas the trays other than a tray above the recording/reproducing unit arepushed by the tray triggering unit, and all driving gears are driven ata same time as one body such that the tray driving gear unit moves alltrays other than the tray above the recording/reproducing unit toprotrude outward from the mechanical chassis to the disc exchangeposition at a same time, and wherein the tray driving gear unit isconfigured to, in a tray closing operation, individually andsequentially move the driving gears engaged with the respective racksfrom top to bottom, such that the tray driving gear unit is capable ofindividually and sequentially driving the trays other than the trayabove the recording/reproducing unit from the disc exchange position tothe standby position from top to bottom in the tray closing operation,whereby each disc on a topmost tray exists at the disc exchange positionin the tray closing operation such that the disc on the topmost tray canbe checked until the topmost tray is closed.
 3. A disc changer forstoring a plurality of discs, transporting a disc selected from theplurality of discs, and performing recording/reproducing of aninformation signal on the disc, the disc changer comprising: a pluralityof trays which respectively can be loaded with discs, can be movedsubstantially in a horizontal direction parallel to main surfaces of thediscs, and are stacked substantially in a vertical directionperpendicular to the main surfaces of the discs; a tray driving gearunit which has a plurality of driving gears capable of respectivelyengaging with a rack provided on each tray, such that the tray drivinggear unit is capable of shuttling the trays between a standby positionin which the trays are stored in a mechanical chassis as a housing ofthe disc changer and a disc exchange position in which the trays areprotruded outward from the mechanical chassis such that the discs can beput on the trays and removed from the trays; a gear driving mechanismdriven by an electrical motor to generate a driving force for drivingthe tray driving gear unit; a tray triggering unit capable oflocking/unlocking the trays in the standby position, the tray triggeringunit being capable of pushing all trays at a same time so as to engagethe rack provided on each tray with a respective driving gear of thetray driving gear unit after unlocking the trays; arecording/reproducing unit for recording and/or reproducing aninformation signal on a disc placed on a turntable; and an elevationunit capable of moving the recording/reproducing unit with the turntablein the vertical direction to align the recording/reproducing unit to atray and place a disc on the tray onto the turntable, wherein the traydriving gear unit and the tray triggering unit are configured such that,in a tray opening operation, the tray driving gear unit rotates to RESETcondition in which all driving gears can rotate in a same direction allat once as one body, the trays at the standby position not being engagedwith the tray driving gear unit after the tray driving gear unit rotatesto RESET condition, the tray triggering unit moves and pushes the traysto engage with the respective driving gears of the tray driving gearunit, and all driving gears are driven at a same time as one body so asto drive the trays to the disc exchange position at a same time, andwherein the tray driving gear unit is configured to, in a tray closingoperation, individually and sequentially move the driving gears engagedwith the respective racks of the trays from top to bottom so as toindividually and sequentially move the trays from the disc exchangeposition to the standby position from top to bottom.
 4. A disc changeraccording to claim 3, wherein the tray driving gear unit is providedwith a shaft gear body, comprising a shaft gear connected to a drivingsource and a shaft on which the driving gears are mounted and stacked ina laminated manner, and each tray is driven by a single driving gear. 5.A disc changer according to claim 3, wherein the tray driving gear unitis provided with a shaft gear body, comprising a shaft gear connected toa driving source and a shaft on which the driving gears are mounted andstacked in a laminated manner, wherein a top level driving gear is fixedto the shaft gear body and rotates as one body therewith at all times,and wherein each driving gear has a rib profile with a stopper ribextending parallel to an axis of the shaft by a predetermined amount,such that when the stopper rib of an upper level driving gear pushes tothe stopper rib of a lower level driving gear in a rotational directionof the upper level driving gear, the lower level driving gear is forcedto rotate in the rotational direction of the upper level driving gear.6. A disc changer according to claim 5, wherein at least one spacer ringis provided between two driving gears adjacent to each other, such thatthe spacer ring allows the upper level driving gear to have anadditional rotation before it drives the lower level driving gear, andthereby the additional rotation is provided to each driving gear.
 7. Adisc changer according to claim 6, wherein the at least one spacer ringhas stopper ribs which are the same as the stopper ribs of the drivinggears, the size in a rotational direction of the stopper ribs isdesigned to be equivalent to a multiple of gear teeth pitching angle,and the teeth of the driving gears align after all stopper ribs contacteach other, and thereby all the driving gears can be driven to move alltrays to the disc exchange position evenly.
 8. A disc changer accordingto claim 7, wherein a total rotational stroke of a driving gear before alower level driving gear starts to rotate is equivalent to a totalstroke for moving a tray from the disc exchange position to the standbyposition.